Measuring system

ABSTRACT

A system for measurement is provided. The system includes a scanning interface module for placement on a skin for non-invasive scanning. The scanning interface module includes a cavity to be pressed on the skin to make a vertical portion in the cavity, and a nonlinear optical system for scanning the vertical portion via an input side and an output side of the cavity that are laterally facing each other.

TECHNICAL FIELD

The invention generally relates to a system for measuring under the skin in a non-invasive manner.

BACKGROUND ART

An apparatus for measuring a physical parameter, such as the saturation percentage of oxygen in blood is disclosed in U.S. Pat. No. 5,792,052. In this apparatus, the pulse oximeter is built into the finger clip, and therefore the device is small, lightweight and very portable, as well as more reliable.

SUMMARY OF INVENTION

For measuring a physical parameter, nonlinear optical spectroscopy method is one of the suitable methods for non-invasive detection of components under the skin. However, there are limits on the ability to penetrate scattering mediums and maintain the characteristics such as phase and polarization requirements necessary to achieve the nonlinear interaction necessary to achieve the nonlinear emission process. For non-invasive scanning where we need to focus on capillary structures, many of the target regions would require a backscattered signal which is often substantially weakened, or have to go through thick regions of tissue which would degrade the necessary phase and polarization requirements.

One aspect of this invention is a system comprising a scanning interface module for placement on a skin for non-invasive scanning. The scanning interface module includes a cavity to be pressed on the skin to make a vertical portion in the cavity and a nonlinear optical system for scanning the vertical portion via an input side and an output side of the cavity that are laterally facing each other. In the system of this invention, by pressing the cavity of the scanning interface module on the skin, the structure can be made with little strain on the skin, with a narrow area where the skin sticks out just a little as the vertical portion, and is suitable for measuring using the nonlinear optical spectroscopy. In one of embodiments, the shape of the vertical portion may have a region that is less than 1 mm in lateral distance and less than 500 fÊm in vertical depth. The region may be less than 500 fÊm in lateral distance and less than 300 fÊm in vertical depth. The cavity size may be of a size suitable for forming such a vertical portion, that is, an opening diameter of the cavity may be about 1 mm or less and the depth may be about 500 fÊm or less. The opening diameter of the cavity may be about 500 fÊm or less and the depth may be about 300 fÊm or less.

The system may include a finger clip type housing that received the scanning interface model so that the cavity faces an area adjacent or including nail bed. One of the areas that are suitable for measuring components of blood using the nonlinear optical system is the cuticle region where the capillary structures are within 200 to 300 fÊm below the surface especially the area including or the adjacent nail bed where the capillary bed is often present. One of the nonlinear optical systems that are suitable for this system is a CARS (Coherent Anti-Stokes Raman Scattering) optical system, in which the Stokes light and the pump light, in some embodiments the probe light, are inputted via or through the input side of the cavity and the scattered light (CARS light) from the vertical portion is outputted via or through the output side of the cavity. The nonlinear optical system may be another Raman optical system such as a SRS (Stimulated Raman Scattering) system, or other optical systems that use the nonlinear optical processes or non-linear optical spectroscopy.

BRIEF DESCRIPTION OF DRAWINGS

The embodiments herein will be better understood from the following detailed description with reference to the drawings, in which:

FIG. 1 depicts an embodiment of a system of this invention;

FIG. 2 depicts an outline of vertical portion;

FIG. 3 depicts an overview of scattering; and

FIG. 4 depicts a flowchart showing an overview of the process in the system.

DESCRIPTION OF EMBODIMENTS

The embodiments herein and the various features and advantageous details thereof are explained more fully with reference to the non-limiting embodiments that are illustrated in the accompanying drawings and detailed in the following description. Descriptions of well-known components and processing techniques are omitted so as to not unnecessarily obscure the embodiments herein. The examples used herein are intended merely to facilitate an understanding of ways in which the embodiments herein may be practiced and to further enable those of skill in the art to practice the embodiments herein. Accordingly, the examples should not be construed as limiting the scope of the embodiments herein.

FIG. 1 illustrates a system 1 according to an embodiment of this invention. The system (measuring system, monitoring system, analyzing system) 1 shown in FIG. 1 is a finger clip type device that can be worn on a fingertip 5 of a user. The finger clip type device is one of the examples of the system 1 of this invention implemented in a wearable device. The system 1 may be another wearable device, such as a smartwatch, smart glasses, and others.

The system 1 includes a scanning interface module 10 for placement on a skin 6 of the finger 5 for non-invasive scanning. The scanning interface module 10 includes a cavity 12 to be pressed on the skin 6 to make a vertical portion 7 in the cavity 12, and a nonlinear optical system 20 for scanning the vertical portion 7 via an input side 13 and an output side 14 of the cavity 12 that are laterally facing each other. The system 1 further includes a generator (laser module) 30 configured to generate a light 31 for generating signals for analyzing an object through the nonlinear optical system 20, a detector 40 configured to detect a light 35 including the signals from the object acquired by the nonlinear optical system 20 and a display device 51 for outputting analysis results of detected signals by the detector 40. The system 1 further includes a finger clip type housing 60 that received the scanning interface module 10 so that the cavity 12 faces an area 8 adjacent or including the nail bed 4 near the nail 3.

The housing 60 includes an upper part 61, a lower part 62 and a connector 63 for connecting the upper part 61 and the lower part 62 to grip the inserted FIG. 5 . The connector 63 may include a spring or other parts to press the scanning interface module 10 to the skin 6 by sandwiching (cramping, holding or pinching) the finger 5 between the upper part 61 and the lower part 62. The housing 60 may include other parts that allow the housing 60 to function as a finger clip. The upper part 61 to be located on the nail 3 side of the finger 5 receives the optical system 20 and the display device 51 that may include a touch panel function. The system 1 may further include a controller (processor) 50, a memory 53 and an analyzer 45 to make the system 1 function with a measurement device for a given purpose, for example, a blood glucose level measurement device. The controller 50, the memory 53 and the analyzer 45 may be received in the upper part 61.

The system 1 may further include a battery 59 for power supplying to the laser module 30, the controller 50, the display 51 and others housed in the housing 60. The laser module (generator) 30 and the battery 59 may be located in the lower housing 62. The system 1 shown in FIG. 1 is one of embodiments where the scanning interface module 10, the optical system 20, the laser module 30, the detector 40, the display 51, the controller 50 and others for configuring the system 1 are housed in the housing 60 and the system 1 is provided as a single or integrated unit. The laser module 30, the detector 40 and the display 51 may be provided separately from the housing 60 and connected using optical fibers, cables, and/or wired or wireless networks. The system 1 may include other devices or modules to measure other biologic parameters, such as a pulse oximeter in the housing 60.

The object or target to be measured by this system 1 is one or more components of blood in the blood capillaries (vessels) 9 of the capillary bed 90. The typical component to be measured is blood glucose. The objects (target components) may include, in addition to glucose, hemoglobin Alc, creatinine, albumin, biomarkers and other biomaterials in the blood.

The nonlinear optical system (optical module) 20 may be a CARS optical module and the laser module 30 may be a generator for generating the Stokes light 32, the pump light 33 and the probe light 34 as the laser light 31 supplied to the optical system 20 via an optical fiber 39 for generating a scattered light (CARS) light 35 in the vertical portion 7. The pump light 33 may also serve as the probe light 34. The laser module 30 may generate the Stokes light 32 having a range of wavelengths 1085-1230 nm, pump light 33 having a rage of wavelengths 1040 nm, and the probe light 34 having a range of the wavelengths 780 nm from a laser source such as a fiber laser source.

In the nonlinear optical system 20, through an object lens system (object lens) 21, the Stokes light 32, the pump light 33 and the probe light 34 supplied by the optical fiber 39 are emitted via the input side 13 of the cavity 12 and the CARS light 35 generated in the vertical portion 7 is received or acquired by a receiver 27 via the output side 14 of the cavity 12 located on the opposite side of the input side 13. The input side 13 and the output side 14 may include one or more apertures or slits for lights to pass through the wall of the cavity 12. The CARS light 35 may be a TD-CARS (time delay CARS, time dependent CARS) light 35 having a range of the wavelengths 680-760 nm generated in the vertical portion 7 using the probe light 34 with some time delay.

One of examples of the receiver 27 that acquires the CARS light 35 is an input lens for guiding the CARS light 35 to an optical fiber for supplying the light 35 to a detector such as a spectrometer or photo detector array (CCD). The receiver 27 may also serve as the detectors 40 and have a function that allows receiving the light (CARS light) 35 via the output side 14 of the cavity 12 in a position adjusted vertically with respect to the cavity 12. The receiver 27 included in this optical module 20 may be a photodetector array that allows receiving and measuring (recording) the position where the light was received and the intensity for each position. The optical system 20 may include an actuator 22, such as a piezo actuator, for adjusting a position of the object lens 21 vertically to move the irradiating light 31 supplied via the optical fiber 39 from the laser module 30, vertically with respect to the cavity 12, and enable the receiver 27 to receive the CARS light 35 in a position adjusted vertically with respect to the cavity 12.

FIG. 2 show a typical vertical portion 7 made by the cavity 12. One area of potential opportunity is the cuticle region where the capillary structures are within 200 to 300 um below the skin surface. By pressing the cavity 12, the vertical portions (vertical structures) 7 can be made on or adjacent nail bed 4 where the capillary bed 90 that includes multiple capillaries 9 is usually located. The cavity 12 may have the shape that allows to make the vertical portion 7 that has less than 1 mm in lateral distance L1 (500 um preferred) and less than 500 um in vertical depth V1 (300 um preferred) by being pressed into the cavity 12. The cavity 12, as shown in FIG. 1 , may have an opening w1 with a diameter or a wide about 1 mm or less and a depth d1 about 500 fÊm or less. The opening w1 may be about 500 fÊm or less and the depth d1 may be about 300 fÊm or less.

A conformal mount is used in this finger clip type system 1 to force a small portion of the cuticle into an elevated region (vertical portion) 7. An adjustment (actuator) 22 may be provided to allow vertical translation of the beam 31 from the optical lens 21. Confirmation of the focus in the capillary bed 90 occurs when a pulse signal is detected by the detector 40.

As shown in FIG. 3 , while the reverse scattering (EPI) results in only 1% signal pickup if the emission is in the capillary bed 90, the generating forward CARS emission in human tissue may generate multiple forward scattering events. But these emissions are very inefficient to recollimate which is necessary to focus into a spectrometer. Use of a swept source laser 31, for example using variable wavelength Stokes light 32 and/or variable wavelength pump light 33, allows elimination of the collimation lens and spectrometer. A large area photodetector, which is applied as the receiver 27 and the detector 40 in this embodiment, can be used to pick up random scattered signals. The photodetector scan timing is synced with the laser sweeping to track what wavelength is being excited. A coating on the photodetector array may be provided to block the excitation signals and only allow emission signal pickup.

The nonlinear optical system 20 may include a reduced NA objective lens 21 that allows for an extended Rayleigh range to eliminate need to focus on a single capillary 9 in the vertical portion 7 made by the cavity 12. In the nonlinear optical system 20, reduced NA lens systems may be applied to both the object lens 21 and receiver side 27 to be coupled to fibers on both input side 13 and output side 14 of the cavity 12. The object lens 21 and the receiver 26 may be positioned laterally and may be adjusted vertically with respect to the conforming cavity 12 to vertically scan the vertical portion 7 by the horizontal lightings generated or emitted by the nonlinear optical system 20. This allows some depth adjustment to account for individual differences in finding the capillary bed 90. The use of a reduced NA objective lens 21 (compared to typical nonlinear optics) allows for an extended Rayleigh range to eliminate the need to focus on a single capillary 9 in the capillary bed 90. The optical system 20 then scans the entire capillary bed 90 within the cavity 12 and gives a response that varies with pulse rate. A unique NR reference scheme is employed to utilize the base levels of this signal as a NR reference and normalize the strongest signals relative to this base.

The controller 50 of this system 1 includes a processing module 50 a for controlling the entire system including user interface using display device 51 and a processing module 50 b that subtracts signals of lights acquired at different vertical positions. In the optical system 20, by adjusting the vertical position relative to the cavity 12 using the object lens 21 and/or receiver 27, signals from the lights 31 passing through the different vertical position (different depth or height) of vertical portion 7 can be obtained by the detector 40. Such signals may contain the signals of the light passing through the edge of the capillary bed 90, the signals of the light passing through the center of the capillary bed 90, and the signals of the light passing through a part without the capillary bed 90. Such signals may contain the information of (blood+surroundings), (blood+More Blood+surroundings) and (only surroundings). Therefore, the processing module 50 b, by subtracting these signals each other, can generate signals that contain mainly information about the components in the blood and little information about the surrounding. Functions of these modules 50 a and 50 b may be implemented in the processor 50 using a program (program product) 53 a stored in the memory (memory medium readable by a processor or a computer) 53.

FIG. 4 depicts a flowchart showing an overview of the process (controlling) in the system 1. In step 81, under the control of the controller 50, the signals from the light passing through various heights (vertical positions) are acquired. In step 82, the signal or signals with high intensity of the component to be measured (target object) is selected. In step 83, the module 50 b generates the signals for analyzing by subtracting signals of lights acquired at different vertical positions to reduce influence of components other than blood. In step 84, controller 50 outputs the information about the component or components that are the targets of the measurement by analyzing the signal.

As explained above, in this invention, a biomechanical interface for non-invasive cuticle scanning is provided. Using nonlinear optical spectroscopy methods, there are limits on the ability to penetrate scattering mediums and maintain phase and polarization requirements necessary to achieve the nonlinear interaction necessary to achieve the nonlinear emission process. For non-invasive scanning where we need to focus on capillary structures, many of the target regions would require a backscattered signal which is often substantially weakened, or have to go through thick regions of tissue which would degrade the necessary phase and polarization requirements. One area of potential opportunity is the cuticle region where the capillary structures are within 200 to 300 fÊm below the surface. The challenge here is that the structures are vertical and with the adjacent nail bed, which limits the degree to which they can conform. The proposed concept uses a multi-curve shape to support a limited degree of conformal behavior. The shape allows a region that is less than 1 mm in lateral distance (500 fÊm preferred) and less than 500 fÊm in vertical depth (300 fÊm preferred) to be pressed into a cavity that can be horizontally scanned by a nonlinear optical system. A reduced NA lens system coupled to a fiber on both input and output sides are positioned laterally and can be adjusted vertically with respect to the conforming cavity. This allows some depth adjustment to account for individual differences in finding the capillary bed. The use of a reduced NA objective lens (compared to typical nonlinear optics) allows for an extended Rayleigh range to eliminate the need to focus on a single capillary. The probe then scans the entire capillary bed within the cavity and gives a response that varies with pulse rate. A unique NR reference scheme is employed to utilize the base levels of this signal as a NR reference and normalize the strongest signals relative to this base.

The foregoing description of the specific embodiments will so fully reveal the general nature of the embodiments herein that others can, by applying current knowledge, readily modify and/or adapt for various applications such specific embodiments without departing from the generic concept, and, therefore, such adaptations and modifications should and are intended to be comprehended within the meaning and range of equivalents of the disclosed embodiments. It is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation. Therefore, while the embodiments herein have been described in terms of preferred embodiments, those skilled in the art will recognize that the embodiments herein can be practiced with modification within the spirit and scope of the appended claims. 

1. A system comprising a scanning interface module for placement on a skin for non-invasive scanning, wherein the scanning interface module includes a cavity to be pressed on the skin to make a vertical portion in the cavity, and a nonlinear optical system for scanning the vertical portion via an input side and an output side of the cavity that are laterally facing each other.
 2. The system according to claims 1, further comprising a finger clip type housing that received the scanning interface model so that the cavity faces an area adjacent or including nail bed.
 3. The system according to claim 1, further comprising: a generator configured to generate a light for generating signals for analyzing an object through the nonlinear optical system; and a detector configured to detect a light including the signals from the object acquired by the nonlinear optical system.
 4. The system according to claim 3, further comprising a display device for outputting analysis results of detected signals by the detector.
 5. The system according to claim 1, wherein the nonlinear optical system includes a receiver that allows receiving light via the output side of the cavity in a position adjusted vertically with respect to the cavity.
 6. The system according to claim 5, further comprising a processing module that subtracts signals of lights acquired at different vertical positions.
 7. The system according to claim 1, wherein the nonlinear optical system includes a reduced NA objective lens that allows for an extended Rayleigh range to eliminate need to focus on a single capillary in the vertical portion made by the cavity.
 8. A method including acquiring signals for analyzing components in blood capillary using a scanning interface module for placement on a skin for non-invasive scanning, wherein the scanning interface module includes: a cavity to be pressed on the skin to make a vertical portion in the cavity; a nonlinear optical system for scanning the vertical portion via an input side and an output side of the cavity that are laterally facing each other; and a receiver that allows receiving light via the output side of the cavity in a position adjusted vertically with respect to the cavity, and the acquiring signals includes subtracting signals of lights acquired at different vertical positions to reduce influence of components other than blood. 